ABST R AC T VOLU M E 4th INTERNATIONAL
PALAEONTOLOGICAL CONGRESS
The history of life: A view from the Southern Hemisphere
September 28 – October 3, 2014 MENDOZA, ARGENTINA
4th IN T E R NAT IONAL PAL AEON TOLOGIC AL CONGR ESS T H E H ISTORY OF LI F E : A V I E W F ROM T H E SOU T H E R N H E M ISP H E R E
ABST R AC T VOLU M E Compiler
Esperanza CERDEÑO | IANIGLA, CCT-CONICET Mendoza. Argentina
Graphic design: Remedios MARÍN | CCT-CONICET Mendoza. Argentina Text composition: Silvina Laura PEREYRA | CCT-CONICET Mendoza. Argentina
Open sessions / Poster
A N E W LOW E R C A M BR I A N R ELIC T OF W EST E R N P E R IGON DWA NA I N GE R M A N Y (SA XOT H U R I NGI A N ZON E , NORT H E A ST E R N BAVA R I A) Hans-Georg Herbig1 and Thomas Wotte1 1. Universität zu Köln, Institut für Geologie und Paläontologie, Zülpicher Str. 49a, Köln, D-50674, Germany.
[email protected]
Calcimicrobe-archaeocyathid-bearing carbonate rocks are typical for the shallow platform realms of the low- to mid-latitude western Perigondwana realm. The facies is well-known from the Moroccan Antiatlas, the Iberian Peninsula (Sierra Morena, Cantabrian Mountains), southern France (Montagne Noire) and Sardinia. Few isolated occurrences in Central Europe prove the dispersion of peri-Gondwana terranes belonging to the Armorican terrane assemblage. Archaeocyathid-bearing carbonates have been reported from recrystallized and metamorphic rocks of the Bohemian Massif (Poland, Czechia). In Germany, they are well-known from subsurface of the Saxothuringian Zone in the vicinity of Leipzig (Saxonia, Doberlug-Torgau-Delitzsch syncline). Herein, we report a new discovery from the Saxothuringian Zone in northeast Bavaria (Franconian Forest, southern Germany). Middle Cambrian siliciclastic strata have been known since decades from the region, but this is the first proof of Cambrian carbonate rocks and the first definite proof of the lower Cambrian. The occurrence was originally described as a several meter big lens of “algal limestone” within the late middle Viséan/early late Viséan “Heinersreuth Blockkonglomerat”. The conglomerate belongs to a Viséan wildflysch succession in front of the Variscan orogen and consists of different lithotypes, reworking a variable suite of Cambrian to Carboniferous sedimentary rocks. New observations prove that instead of a single slide block, a couple of isolated and disoriented, debris flow-related limestone blocks are preserved. Several carbonate microfacies occur. Most spectacular is a calcimicrobearchaeocyathid boundstone with two types of abundant Epiphyton tufts. Irregular and regular archaeocyathids, Girvanella and Kordephyton tufts are associated. Encrusting bubble-like structures appear to be juvenile archaeocyathids. A microbial bindstone, in cases with abundant Girvanella, consists of stacked mats, often strongly micritized into spongiostromatic masses. Occasionally the mats are separated by quartz-rich layers, which might give rise to irregular stylo-bedding. The mats might be also reworked as algal biscuits forming flat-pebble conglomerates. Biostratigraphic data still have to be acquired. However, the striking facies similarity of the calcimicrobe-archaeocyathid boundstones from the subsurface of Saxonia, which are all of Atdabanian age, favour the same age for the occurrence from the Franconian Forest.
4th INTERNATIONAL PALAEONTOLOGICAL CONGRESS, Mendoza, Argentina. 2014
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